Phonograph



Nov. 10, 1936. B. A. PRocToR PHONOGRAPH Filed April 24, 1934' 2 Sheets-Sheet 1 n Am 6 m E N M WAYi W T Nov. 10, 1936. B. A. PROCTOR PHONOGRAPH Filed April 24, 1934 2 Sheets-Sheet 2 hmt IN VEN TOR Barron A. Procfor:

72pm 9 ATTORNEYS.

Patented Nov. 10, 1936 UNITED STATES PHONOGRAPE Barton A. Proctor, Larchmont, N. Y., assignor to B. A. Proctor Company, Inc., New York, N. Y., a corporation of New York Application April, 1934, Serial No. 722,110

This invention relates to phonographs. It is particularly concerned with a mechanical device of the nature-of a rigid, swinging arm adapted to support either a translating device, preferably of the type which employs a piezo-electric crystal for translating the recorded sound waves into electrical vibrations, or a similar device for translating electrical vibrations into sound waves for completing a sound record.

I shall describe a preferred form of embodiment of the invention and then point out the novel features thereof in the claims.

In the accompanying drawings,

Fig. 1 is a plan view of a preferred form of embodiment of a reproducer constructed in accordance with the present invention.

Fig. 2 is a longitudinal section of Fig. 1 along lines II--II looking in the direction of the arrows.

Fig. 3 is a circuit'diagram showing one form of circuit in which the reproducer of the present invention may be employed.

Fig. 4 is a section of Fig. 2 along the lines IV--IV looking in the direction of the arrows, and

Fig. 5 is a view similar to Fig. 4 but showing a modification thereof.

Similar characters of reference designate similar parts-in each of the several views.

I will now describe the invention as embodied in a structure of the nature of a pick-up arm or reproducer, this particular physical embodiment being, however, merely illustrative.

In the drawings reference character I designates a record which is to be reproduced and 2 a turntable of conventional type on which the record is supported during the reproducing process. The pick-up arm is designated generally by numeral 3. It will be observed that this pickup arm is pivotally mounted on a forked bracket 4, which bracket is free to rotate about a vertical bearing 5 provided in the pivot mounting 5. This mounting consists of a base portion 6 which is secured by screws 1 on a table or other stationary support. Integral with base 6 is an upright member 8 having at its upper end a horizontal portion 9. The vertical bearing 5 for the forked bracket 4 is formed by a pair of self-aligning ground cone ball bearings, comprising cone members i0 and II, united to each other by a bolt l2. Cones i0 and II cooperate with races l3 and 14 provided in the vertical portion l5 of bracket 4.

From the above descripton it will be seen that bracket 4 is free to swing in a horizontal plane and that the ball bearing mounting for the bracket is such that the bearings are self-centering and are capable of taking both radial and thrust be adjusted according to requirements.

12 Claims. (Cl. 179-100.41)

strains. The cones l0 and H and races l3 and i 4 are preferably constructed of hardened metal and ground to shape. Upper cone III is preferably provided with recesses lG-for receiving the pins of an adjusting tool so that by turning the cone with reference to threaded bolt l2 the play of the bearings may be taken up and adjusted to any desirable degree. The projecting end of horizontal portion 9 of the vertical pivot mounting 5 is; preferably split as shown at l9, Fig. 1, and a screw is threaded in this split portion,

so that after proper adjustment of the bearing.

member ID, the latter may be locked in position by the tightening of screw 20.

Adjacent their outer ends, forks I1 and I8 are provided with a bearing 2! for pick-up arm 3. This bearing is exactly similar in construction to vertical bearing 5 and need not, therefore, be described in detail. By virtue of bearing 2|, pick-up arm 3 is free to swing in a vertical plane. It will thus be noted that the pick-up arm 3 is free to swing with absolute freedom of movement in both vertical and horizontal directions.

The pick-up arm 3 is preferably channel shaped in cross section at its outer end, so that maximum rigidity may be obtained. At its inner end it is provided with a counterweight 22 which is slidable on arm 3. A clamping screw 23 having a spring 24 and a nut 25 is provided to hold the counterweight in any desired position. The scale 26 is desirably mounted on pick-up arm 3 and is graduated to read in ounces of needle pressure, depending upon the adjustment of the weight 22. A projection 21 from the end of the pick-up arm is provided to cooperate with a. stop 23 mounted on bracket 4 by a screw 29. Stop 28 bears-the unbalanced weight of pick-up arm 3 when the latter is swung clear of the record I.

Adjacent its outer end the pick-up arm 3 is provided with a weight which consists of a pair of discs 30 and 3|. These discs are mounted on the pick-up arm by means of a bolt 32 which extends through an opening 33 in the pick-up arm, a sleeve 34 of soft rubber or other vibration dampening material being provided on bolt 32. Springs 35 and 36 coiled about bolt 32 are provided to hold discs 30 and 3| spaced from the pick-up arm. .By changing the compression of springs 35 and 36, the periodicity of the system comprised of pick-up arm 3, springs 35 and 36 and discs 30 and 3| may be changed. The natural period of vibration of the pick-up arm may thus Resonance points within the audible range may thus be avoided.

The piezo-electric crystal element, designated by reference character 31, is mounted in the pickup arm by means of screws 38 and 39. This element may be of standard construction available on the market and is therefore not described herein in detail. Its mode of operation may desirably be in general similar to that disclosed in U. 8. Letters Patent to Hough, No. 1,761,831. The needle member 40 of the crystal reproducer is mounted therein by a set screw 4 I. The leads." which come from the crystal are preferably supported in the pick-up arm by means of clips 43 and 44 and pass through an opening II in the base of the vertical pivot member.

In the diagram of Fig. 3, the conductors 42 are shown connected to a transformer ii, the primary winding of which has a plurality of taps 41. The secondary winding of' the transformer leads through the conventional type of volume control resistance net-work, from which connections lead to the input side of an amplifier 49. The loud speaker connected to the output side of the am-- plifier is indicated at iii.

In Fig. 5 is shown a modification of the mounting of the discs 30 and 3|. This modification consists in the provision of soft rubber sleeves BI and B2 to take the place of sleeve 34 and coil springs 35 and 38. These rubber sleeves engage in the transverse opening 33 of the pick-up arm and serve, thus, to act also as a dampening connection between the discs and the pick-up arm. Sleeves 5| and 52 are maintained under adjustable stress by the bolt on which they are mounted, in a manner similar to the mounting of springs 35 and 36 as shown in Fig. 4.

While the above description has had reference to the particular physical embodiment shown in the drawings, where a reproducer is illustrated, it will be understood that where the invention is to be used for recording a suitable form of translating device will be used for that purpose, at 31.

I have described what I believe to be the best embodiments of my invention. I do not wish, however, to be confined to the embodiments shown, but what I desire to cover by Letters Patent is set forth in the appended claims.

I claim:

1. In a phonograph, a rigid arm, a translating element carried by the outer end of said arm, a counterweight on the inner end of said arm, a forked bracket, a horizontal pivotal connection between said arm and said forked bracket, a vertical bearing member and a vertical pivotal connection between said forked bracket and said vertical bearing member, comprising bearing members disposed above and below said forked bracket, said horizontal and vertical pivotal connections being respectively constructed and arranged to restrict said arm to oscillation in a vertical plane in said forked bracket and to restrict said forked bracket to oscillation in a horizontal plane around its vertical bearing, whereby all torsional aberration of said parts is prevented and said translating element is supported-rigidly in all of its possible adjustive and operative positions.

2. The combination of claim 1, in which the horizontal connection comprises a pair of selfaligning cone ball bearings and means for taking up play in said bearings.

3. In a phonograph, a rigid arm, a translating element carried by the outer end of said arm, a forked bracket, a horizontal pivotal connection between said arm and said forked bracket, a vertical bearing member and a vertical pivotal connection between said forked bracket and said vertical bearing member, a weight and means for mounting said weight adjacent to the outer end of the arm, said means comprising a resilient member maintained under stress interposed between the weight and the arm.

4. In a phonograph, a rigid arm, a translating element carried by the outer end of said arm, a forked bracket, a horizontal pivotal connection between said arm and said forked bracket, a vertical bearing member and a vertical pivotal connection between said forked bracket and said vertical bearing member, a weight, and means for mounting said weight adjacent to the outer end of the arm, said means comprising a bolt passing through an opening in the arm, and a resilient member maintained under stress between said bolt and said arm.

5. In a phonograph a. rigid arm, a translating element carried by the outer end of said arm, a

counterweight on the inner end of said arm, a

forked bracket, a horizontal pivotal connection between said arm and said forked bracket. a vertical bearing member and a vertical pivotal connection between said forked bracket and said vertical bearing member, a weight comprising a plurality of discs, means for mounting said discs adiacent to the outer end of the arm, said means comprising a bolt fastened through an opening in the arm' and through the center of each disc, one disc being on each side of the arm, resilient material interposed between said discs and said arm, and means for adjusting the compression to which said resilient means is subjected.

6. In a phonograph, a rigid arm, a translating element carried by the outer end of said arm, a counterweight on the inner end of said arm, a forked bracket, a horizontal pivotal connection between said arm and said forked bracket, a vertical bearing member and a vertical pivotal connection between said forked bracket and said vertical bearing member, a plurality of discs, a bolt passing through said discs and through an opening in the arm, a pair of springs coiled about said bolt and interposed between said discs and said arm, and a rubber sleeve between said bolt and said arm.

7. In a phonograph, a rigid arm, a translating element carried by the outer end of said arm, a counterweight on the inner end of said arm, a forked bracket, a horizontal pivotal connection between said arm and said forked bracket, 9. vertical bearing member and a vertical pivotal connection between said forked bracket and said vertical bearing member, a plurality of discs, a bolt passing through the center of each disc and through an opening in the arm, a plurality of resilient sleeves interposed between said discs and the arm, and a nut on said belt for co-operating with said bolt and said discs for placing said sleeves under varying degrees of compression.

8. In a phonograph, in combination, a support, a bracket horizontally pivoted thereon, a rigid arm vertically pivoted on the bracket, a translating device including a stylus at the outer end of said arm for resting on a phonograph record, and means carried at the outer end of the arm in proximity to said translating device for modulating the natural period of vibration of the arm while maintaining the gravitational coeflicient of the translating device and its associated parts, and thus preventing the setting up of secondary vibrations of audible frequencies in said arm, said means comprising a weight and a complemental resilient member maintained under, stress.

9. In a. phonograph, a rigid arm, a translating element carried by the outer end of said arm, a forked bracket, a horizontal pivotal connection between said arm and said forked bracket, a vertical bearing member, and a vertical pivotal connection between said forked bracket and said vertical bearing member, a weight and means for mounting said weight adjacent to the outer end of the arm, said means comprising a resilient member maintained under stress between said weight and said arm.

10. A phonograph, comprising the elements combined and co-operating as set forth in claim 1, and further characterized by having said vertical bearing constituted by a pair of self-aligning cone-ball bearings, one member of the pair being disposed above and the other member below, the horizontal plane of oscillation of the forked bracket, thereby to prevent aberrations of the forked bracket from its horizontal path.

11. A phonograph comprising the elements combined and co-operating as set forth in claim 1, and further characterized by having said horizontal bearing constituted by a pair of self-aligning cone ball bearings, one member of said pair being disposed at one side of the vertical plane of'oscillation of said am in the forked bracket, and the other member being disposed at the other side of said vertical plane and said counterweight being mounted adjustably upon said arm in position to swing through the space between the lines of the forked bracket.

12. In a phonograph, a vertical bearing member, a rigid bracket pivotally mounted in said bearing member and limited to swing freely in a horizontal plane, an arm mounted pivotally at an intermediate point of its length in hearings on said bracket, and limited to swing freely in a vertical plane, a translation device at the outer I end of said arm and a counterweight mounted thereon adjacent to the inner end thereof, said arm being rigid throughout its length from said translating device to said counterweight.

BARTON A. PROCTOR. 

